In certain circumstances, such as closet doors and the like where a latch is not used to keep the door closed, it is desirable to install a dummy knob or lever. Typically, a dummy knob or lever is cheaper to install because it has fewer parts.
Unfortunately, for several reasons, the installation of conventional dummy knobs and levers is considered troublesome to consumers. In a conventional installation, the interconnection between the interior and exterior rose assemblies is established by the use of threaded fasteners. The exterior rose assembly typically includes two internally threaded bosses that align with two apertures formed on the interior rose assembly. Standard machine screws are inserted into the interior rose apertures and are brought into alignment with and threadingly engage the threaded bosses formed on the exterior rose assembly. Tightening the screws closes the interior and exterior roses toward each other, thereby trapping the door therebetween.
There are numerous disadvantages to this conventional method of establishing a semi-permanent mechanical connection between the interior and exterior rose assemblies. In particular, the access to the screw heads may be partially concealed behind the doorknob making manipulation awkward. In addition, the screws typically used for this purpose are relatively long (often 1 inch or more in total length) to permit a single lockset to accommodate doors of varying thicknesses, typically in the range of 1xe2x85x9 to 1xc2xe inches. The length of the screws requires that the screws be turned many times when the doorknob or lever is being installed on thinner doors, thereby reducing the speed of installation. Furthermore, the bosses must be internally threaded deeply enough to accommodate the length of the screws when the doorknob or lever is installed on thinner doors. Such deep internally threaded features are difficult to produce in high volume and add to the cost of manufacture.
The use of conventional machine screws in the installation of the doorknob or lever requires that the installer have an appropriate tool available to drive the screws. The use of such tools in connection with the awkward access to the screw heads due to concealment by the doorknob creates significant risk of cosmetic damage to the interior rose should the tool slip off the screw head. If such damage occurs, the installer may be required to remove and replace the interior rose and knob assembly, particularly in new construction applications. Moreover, the risk of cosmetic damage also discourages the use of power drivers, thereby further reducing the speed of installation.
One attempt to overcome these disadvantages is disclosed in U.S. Pat. No. 5,960,517 to Sprekeler. Sprekeler discloses a knob set that includes a knob with an associated rosette and a mounting plate assembly which is attached to the door by fastening to the door surface. The mounting plate assembly includes two disc portions and an internal diametrally mounted slide plate disposed between the two disc portions. A compression spring urges the slide plate to an engaging position. A pair of lugs projecting from a backing plate formed as part of the rosette engage matching rectangular openings in the slide plate and one of the disc members. The two discs are screwed together from behind to form the mounting plate assembly, and then the mounting plate assembly is screwed to the door from the front. A second mounting plate assembly is screwed to the other side of the door to complete the doorknob assembly.
Sprekeler""s device has several disadvantages. First, each mounting plate assembly includes eight parts, including the spring and screws, which increases inventory costs and the number of manufacturing steps necessary to assemble it. Second, the mounting plate assembly has to be screwed to the door which mars the door and possibly ruins the door for using any other type of knob or lever or handleset. Third, using two full size discs to sandwich the slide plate consumes extra material, thereby increasing manufacturing costs.
Accordingly, a dummy knob assembly that can be easily and quickly installed by a consumer without fear of marring the door or the finish of the doorknob or lever would be welcome by consumers. Moreover, if fewer parts and less material was needed to manufacture the knob assembly, manufacturers could produce such a knob assembly less expensively, thereby benefiting the manufacturer and consumer alike.
The present invention overcomes these and other disadvantages by providing a dummy doorknob or lever that can be quickly and easily installed and uninstalled.
The dummy doorknob or lever comprises an assembly with an exterior knob sub-assembly, an interior rose liner coupled to the exterior knob assembly, a knob catch, a retainer spring, and an interior knob coupled to the knob catch. The interior rose liner includes a pair of annular sleeves and a first boss and the knob catch includes a first projection and a second projection, with the first projection engaging the first boss and the second projection being disposed between the annular sleeves.
The interior rose liner includes a second boss and a stem extending from the boss and the interior knob includes a shank configured to receive the stem. The knob catch includes a central portion defining a central opening configured to receive the second boss and a tooth that extends into the central opening. The second boss includes a slot for receiving the tooth, with the tooth extending into the slot to engage the shank.
The spring is disposed adjacent the knob catch. The knob catch includes a tab extending from the second projection and the spring engages the tab to bias the knob catch toward a locking position. The spring includes a pair of projections that engage the annular sleeves to retain the spring in position adjacent the knob catch.